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MFRC630 TVDD current consumption(ITVDD) is too small

Question asked by Toshihiro Sekioka on Jan 13, 2018
Latest reply on Jan 17, 2018 by Wigros Sun

Hello.

 

I use MFRC630 to communicate with Mifare card.

the datasheet shows IDD(TVDD) is typ.100mA and max.200mA.

AN11019 application notes shows IDD(TVDD) is depends on antenna impedance,

IDD(TVDD) is about 50mA When the impedance is 80OHM.

 

 

I measured my PCB total consumption.

MFRC630 stby --- 7.3mA

MFRC630 ACT(reading from Mifare card, its working fine) --- 26.75mA

current diff --- 19.45mA

 

 

I expected the current diff is IDD(modem on) 17mA + IDD(TVDD) 33mA = 50mA.

however measured current diff was 19.45mA.

(The Supply voltage is 3.3v , IDD(TVDD) will be 33mA)

 

I feel abnormal that the current is too little.
Can the MFRC 630 working by such a small current?

 

 

please help.

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